"I've got it!" said the astronomer. "You are bored with driving, and I am weary of lecturing. Let's exchange places for one night. It will be a refreshing change for both of us. My lecture is all written out word for word, and nobody in the next town knows me by sight anyway." The driver agreed, and the exchange of roles and dress was made. That night the lecture hall filled to capacity. At the appointed time those in attendance heard a flawlessly delivered lecture. At its conclusion the lecturer basked in the euphoric applause. Then came the question and answer period.

"Who discovered Uranus?" came from a boy in the front.

"Uh... William Herschel." He remembered that from somewhere.

"And who discovered Pluto?" continued the boy.

"Aaaa... that would be Clyde Tombaugh." He had read a little.

Then from the back: "Would you please comment on the relative merits of the pulsation instability model and the accretion disk instability model for the explanation of outbursts of cataclysmic variable stars?"

The speaker paused for a moment, then said, "I am surprised that you would bother to ask me such a simple question. To show you how really simple it is I shall have my chauffeur answer it for you."

A noted astronomer was giving a public lecture on the evolution of stars and used the sun as an example. As a star ages and uses up its supply of hydrogen fuel in the center, the star expands and becomes cooler on the surface. It enters the giant phase of its life. The total luminosity increases many times. This will eventually happen to our Sun. The result will be a runaway greenhouse effect. The oceans will evaporate; the atmosphere will become hot and will escape off into space. All life will become extinct.

After the lecture, an elderly gentleman timidly approached the lecturer, and with a very concerned look asked the professor, "Did you say that someday the Sun will become so hot that all life on Earth will die.

"Yes I did," said the astronomer. Then noting the worried look on the man's face added, "But that will not happen for about another five billion years."

The old man breathed a great sigh of relief and said, "Oh, Thank goodness. I thought you said it would happen in five million years."

The mother, trying to teach her child good manners, replied, "Suzi, Don't you know that it is impolite to ask an adult how old they are?"

A bit later, children have short memories, the girl asked her mother another question. "Mommy, how much do you weigh?"

The mother was surprised by the question and again explained to her that such questions were impolite.

The next day, the little girl, curious about her family, asked her mom a difficult question. "Mommy, why did you and Daddy get divorced?"

The mother, thinking how hard it would be to explain this to her young daughter and not wanting to think about it herself, replied, "Suzi, when you are older I will try to explain all this to you."

Later that day, Suzi was playing, told her playmate about how her mother would not answer her questions.

The other girl smiled and said, "Suzi, all that information is on your mother's driver's license."

"Really?" exclaimed Suzi.

"Yes," said the other girl. For grownups, the driver's license is just like a report card. It has all sorts of information like that."

The next day, while her mom was busy with household chores, Suzi got into her mother's purse and found her driver's license. She looked at it really carefully and noted all the pertinent facts.

Later she approached her mother. "Mommy, I know how old you are. You're 37 years old. And I know how much you weigh too. You weigh 140 pounds."

Her mother was very surprised and asked her daughter how she knew that.

Suzi replied, "Mommy, I looked on your driver's license. It is just like a report card and tells all about you. I even learned why you and Daddy got divorced."

"That is not on my driver's license!" her mom exclaimed.

"Yes it is," said Suzi, "it is because you got an F in Sex."